Lift truck with suction counterpoise



Jan. 12, 1965 n. A. HARRIS ETAL 3,155,217

LIFT TRUCK WITH SUCTION COUNTERPOISE Filed June 27, 1961 3 Sheets-Sheet 1 37 DONALD A. HARRIS [3 ROBERT C SHOE/MAKER IN VE/V TORS.

BUG/(HORN, BLORE, KLAROU/ST 8 SPAR/(MAN l5 ATTORNEYS Jan. 12, 1965 D. A. HARRIS ETAL LIFT TRUCK WITH SUCTION COUNTERPOISE 3v Sheets-Sheet 2 Filed June 27 1961 DONALD A. HARRIS ROBERT C. SHOE/MAKER lNVE/VTORS.

BUG/(HORN, BLORE, KLAROU/ST & SPAR/(MAN ATTORNEYS Jan. 12, 1965 D. A. HARRIS ETAL LIFT TRUCK WITH suc'rzon COUNTERPOISE 3 Sheets$heet 5 Filed June 27, 1961 Fig. 5

DONALD A. HARRIS ROBERT C. SHOEMA/(ER INVENTORS.

BUG/(HORN, BLORE, KLAROU/ST 8 SPAR/(MAN ATTORNEYS United States Patent 3,165,217 LIFT TRUCK WITH SUCTION CGUNTERPOISE Donald A. Harris, Yan couver, Wash, and Robert C.

Shoemaker, Portland, Greg, assignors to Hyster Company, Portland, reg., a corporation of Nevada Filed June 27, 1961, Ser. No. 119303 2 Claims. ((11. 214-670 This invention relates to industrial lift trucks. Present industrial lift trucks are equipped with heavy counterweights so that they will not tip during loading a and unloading operations, or when the truck is being picking up or depositing a load.

A more specific object of the invention is to provide a truck having means for temporarily anchoring the truck to a surface on which the truck is traveling to enable the performance of loading and unloading operations, and

wherein the load is located in a balanced or stable positiori on the. truck when the truck is driven from place to place so that counterweights are not required.

Various other objects of the invention will be apparent from the following description taken in connection with the accompanying drawings wherein:

FIG. 1 is a perspective viewof a truck embodying the concepts of the present invention;

FIG. 2 is-a fragmentary vertical section taken along line 2-2of FIG. 1;

FIG. 2A is a fragmentary vertical section through a caster wheel structure; I

FIG. 3 is a top view of a modified form of truck; FIG. 4 is a vertical section taken along line 44 of FIG. 3; and

' FIGS. 5 and 6 show another modified form of truck. Referring to FIGS. land 2, the truck has a body or baseframe 11 including a circular deck 22 equipped with a cylindrical skirt 13. The body is supported by a plurality of caster wheels. 15, which are shown in FIGS. 2

turntable and the base member 11.

3,165,217 Fatenteel Jan. v 12, 1955 A sub-deck is provided a few inches above the floor as shown at 26 and the caster wheels operatewithin cylindricalhousings 21 which are hermetically sealed to subdeck 20 and toupper deck 22. The purpose of this is to reduce to a minimum the volume of air that must be evacuated to anchor the truck.

In order to create a subatmospheric pressure below sub-deck Zlland within the wheel housings, there is an electric air pump 31 (FIG. 2) mounted under the body. There is a battery 33 also mounted under the body and there is a switch 35 (FIG. 1) controlling the energization --of the pump. The electrical conductors for the switch 35 extend through the skirt 13. j The pump 31 has an inlet 36 (FIG. 2) communicating with the underside of subdeck 2% and an outlet communicating with the ambient air through an outlet cpeain 37 best shown in FIG. 1.

Mounted on the body is a turntable 21 maintained in concentric relation "to the base'menlber 11 by a s haft 43' (FIG. 2). Suitable bearings preferably are provided around the periphery of the turntable 41 and between the I Turntable 41 is equipped with gear te'eth42 (FIG. l) projecting beyond the skirt body 13. In driving relation with teeth 42 is gear 4%: driven by an irreversible worm gear set in housing 44 driven by reversible rnotor 45a which is mounted on bracket-35 which in turn is attached to, skirt 13. An additional brace 46 attaches housing 4 to skirt 13. V 7

Fixed to. turntable 41 in symmetrical relation with respect to the center line of the turntable 41 'is a pair of tracks 51 of angle form. A support carriage 53 is slidably mounted on 'the tracks and is driven back and forth along the rack 80 by reversible motor 81 through a nonreversibl'e worm, and gear. The motor 81 and associated 'parts are mounted on the support carriage 53, while rack Sllis secured to the turntable 41.

Fixed centrally to the support carriage 53 is an up standing post 61 (FIG. 2). The sleeve 63 is rotatably receivedby thepo'sL-and slidably mounted on the sleeve is .a load carriage 65 (FIG. 1). An acme or circulating ball screw 67 is mounted on an axis parallel to the axis of the mast-between bearingsmounted on brackets 75 and 66. The latter are secured to sleeve 63. Screw 67 is powered in either direction by motor 68 through an irreversible worm 69 anda Worm gear 70 which is keyed constitue's a part of the carriage and causes the carriage and Each wheel is supportedon a sliding spindle J 23 with a piston 24 'andan O-ring '25 so that the wheels may be retracted whenthe truck is to be anchored to the floor by vacuum] Hydraulic fluid to actuate the pistons is pressurized by a conventional hand pump, later referred I to, which can raise'the truck on the wheels, orlower' it onto. rin1;l8 when desired. Suitable conduits, one 2&3, being shown'in FIG. 2A, extend in sealed relation through the walls of the wheel housings and then through the skirt 13; v I g The lower edge of the skirt 131s equipped with an elastomer lip 17 (FIJGQZ) for contacting the surface 19 when the truck is readyto pick up or deposit a load. It is contemplated that thetruck will be used in places having surfaces against which a'suction may bedrawn. A typical surface would be one formed of concrete.

The rigid steel rim 13 is secured to the body of the truck and runs around the skirt just behind lip 17 and to go up and down as screw 67 rotates. i V

' The load carriage, of which'sleeve 72 is a part, has a 'pairo'f fork arms 89 projecting therefrom for engaging a load; While means' providing forcforward and rearward tilting movement of the-fork arms'relative to the mast are i not shown, 'obvious'ly such an arrangement can be provided. For instance, the forks may be connected to serves the dual purpose of preventing the lip from being I drawn underthe truck and supporting the weight of the truck when ,the latter is anchored to the floor and the wheels are retracted. The principal purpose of the latter.

provision is to give the truck the broadest possible base when: it is called upon to support an overhanging load while held down by vacuum.

a conventional fsub-carria'gewhich is pivotally mounted on the main carriage. The sub-carriage may be provided with a suitable motor and lead screw for tilting the carriag'e, similar to that used for elevatingthe carriage.

Rotation of sleet e63 and all the elements mounted thereon about standing post 61 is causedby motor76,

mounted on support carriage 53, irreversible worm 73 and worm gear 74; the nter being keyed to sleeve 63. f Control leiiers 90 through 93 are provided for motors 63, 76,31, and 45 respectively and aremounted on bracket 85 which is anchoredto skirt 13. Lever Q4 is for load carriage tilt if tilt is provided. Each lever causes its corresponding function to go one direction when lever is pulleda'nd in theopposit'edirection when the lever ispushed and each is detented at the center of hold position. As indicated, all the functions are driven by irreversible worin and gear sets so the established positions will be maintained unless driven one way or the other by the respective motors. Control wires are not shown to the screw. A nut 7l is mounted on a sleeve 72 which 1 it willnot be stable otherwise.

'cient capacity with respect to the area encircled by the- ':elastomer lip 17 to create a sufiicient subatmospheric' 7 pressure within the lip as to anchor the truck to the sur-' 'be provided for anchoring pelled and steered by the operator, who walks behind it and grasps stationary handles 96 and 96'. Larger embodiments of the invention may be power driven.

Operation When the truck is proceeding to pick up a load at floor level, the mast, carriage and forks will be moved to, one

end of tracks 51 so that the forks project beyond the 1 clearance line of the circular base of the truck. :In this position, the forks can be lowered to the ground and the truck can be maneuvered in a conventional manner like any other lift truck. Before picking 'up the load, how

ever, the truck will be anchored to the'floor by vacuum, becauselacking counterweights and a long wheelbase,

' The pump 31 has suitiface upon which it travels so as to-prevent its movement and also tipping thereof. To anchor the truck, the operawhich starts vacuumpump 31. to the floor, all manipulation involved in withdrawing the loadmusttake place on the body of the truck itself because it can no longer movelike a conventional truck. 'It' so that the load can be moved to a position, within the clearance line of thecircular body with its centerof gravity substantially over the wheels; With the load in this position, the operator jacks down the wheels with'lever 95 and moves on.

The unloading operation is the exact reverse of the loading'operation. Prior to depositing the load, the truck must be anchored to the floor by vacuumso that when,

tor lowers .it to rest on rim 18 and engages switch 35 After being anchored.

the load is extended beyond the circular body, it will not tip the truck over. Due to the various motions provided,

however, the load can still be maneuvered into exactposition even though the body of the truck is anchored to 7 Instead of suction counterpoise, suitable magnets couldI the body temporarily to a ferro magnetic floor. v a

FIGS. 3 and 4 show a modified form of invention in which the truck body includes a base member 97a of .circular shape in plan. but having a square recess 97b formedtherein. A skirt 970 shown in FIG. 4 isprovided around the periphery of the base member 97a and the skirt defines a'well at: the recess 97b. The provision of the recess provides the body with a pair of forwardly projecting wings. The body of thetruck is supported by a i a plurality of casters 97d, one of which is shown in FIG. 4

V and is disposed centrally at the rear of the body." There .are other casters with at least one'smallencast'er at the forward end of the .wings of the body. 7

very broad application, however,

atmospheric pressure for the suction 7 of a rotary nut 115a driven by the motor and riding on a stationary screw 11511. A bracket115c supports per end. of the screw. 7

The load carriage 113 has. a pair of horizontal support pieces 116 to which is secured a pair of fork harms 117; While the arms are not mounted for tilting movethe upment, they could be so mounted if desired. It is'pointed out that the width of the'forks is such that they can'fit into the well 97b of the truck body so that the fork arms may be lowered into engagement with the floor while in the position shown in FIG. 3. A suitable handle'121 is provided on the supportcarriage-109 toenable the truck to be moved from place to place and turned by applying lateral pressure to the handle.

I I In operation, it is assumed that the carriage 109 will be braked and the truck is shoved to the desired position by use of the handle 121. Then, a suction 'is drawn in the body of the truck to temporarily anchor thebody to the supporting surface. Thefconstruction is such that a suflicient subatmos pheric pressure can be drawnwithin the area encompassed by the lip 101 as to anchor the truck in'place and preventits movement and also tipping thereof. Thereafter, the brake for the support carriage is released to enable'the support carriage to be shoved for: wardly to insert the fork arms 117 beneath the load. It is pointed out that in this truck, the fork arms can be lowered down to floor level before being inserted beneath a load and therefore this truck can pick up a load at floor level while the base of the. truck is adjacent to the load. This provision allows the truckto load and unload in an aisle very little wider than the diameter of thetrllck. It is obvious that casters similar to those of FIGS. .1, 2 and 2A could be used in the FIGS. .3 and4forn, of the invention. If so, a rim like that used in FIG. iZwoCrld be employed. V I

Many persons have been experimenting with 'side loading and unloading-attachments. These never have had 7 because when the load 1s off to one side as shown. in FIG. "5, the truck is quite unstable and the load must be reduced below a practical limit. We'propose to mount suction cupsy139 and 130',

which can be energized to stabilize the truck against side tipping until the load hasbeen. moved across the face of the carriage 131 so as to centerit. The source of subcups 13.0 and 130 has such a capacity, inl'relation to the area of v the suction cups, as to create .subatmospheric pressure 'sufiicient to anchor thetruck to the floor and prevent its movement and also tipping thereof. There is a retraction mechanism indicated at 132, soithat the suction cups will not There is ,an elastomen flap 101 extending around: the

bottom edge of 'the skirt 97ciin engagement ,with the'fioor.

The body contains a. battery, electric motor and switch similar to the first form of the inventiongbut these are not shown and only a switch handle 103 and an outlet 105 are shownin FIG. 3.

On'the upper surface of the base member 97a is a pair of fixed tracks 1&7 similar to the tracks in the-first form of the invention. A support carriage 109 is slidably mounted on the tracks, for manual movement, a suitable friction ,brake'having a handle 110 being provided on YT the support carriage to enable it to be temporarily locked '75 other than by the drag on the floor during transit. On this truck, which'is normally. equipped for hydraulics, it would naturallyinvolve a cylinder on each cup, It should be. notedthat the attachment should be a loose pivot acting at the center of the cup so as to avoid the possibility of peeling the cup off the floor. Obviously; if the upliftshould be applledat one end of 'the'cup, the cup would be only about half as effective .as it would be iftheforce were applied at'the center of the cup; a

Having described theinvention in what is considered to be the preferred.embodiment'thereof, it is desired that 1t be understood that, the invention is not to be limited provisions of the following claims. We claim: 7 7

beoperat'ed, 1 'load engaging means,

means mounting said load engaging means on said body for movement from a first position to a second position so laterally displaced from said first position as to render said truck unstable when handling a load near the capacity of the truck, 5

and suction means for temporarily anchoring said body to said surface during loading and unloading opera- I tions to prevent/tipping of said body,

said body having a periphery,

said wheels being located within the confines of such 10 periphery,

said suction means extending around such periphery exteriorally of said Wheels.

'2. An industrial lift truck comprising a body having wheels for engaging a surface on which said truck is to 15 be operated,

load engaging means,

-means mounting said load engaging means on said body for movement from a first position to a second position so laterally displacedifrom said first 0 position as to render said truck unstable when handling a load near the capacity of the truck,

suction means for temporarily anchoring said body to said surface during loading and unloading operations to prevent tipping of said body, g 25 means for raising said suction means to a position spaced from said surface and for lowering said suction means for engagement with said surface,

and means for connecting said suction means to a source of subatmospheric pressure to cause said suction means to adhere to said surface and for connecting said suction means to the ambient air to break said vacuum,

said suction means having an effective center Within the wheel base of said truck, 1

said body having a curved periphery,

said wheels being located within the confines of such periphery,

said suction means extending around such periphery exteriorally of said wheels.

References Cited in the file of this patent UNITED STATES PATENTS 371,281 Siemang Oct. 11, 1887 670,391 Robinson Mar. 19, 1901 961,093 Astor June 14, 1910 1,698,482 Nicin Jan. 8, 1922 2,101,399 Larson Dec. 7, 1937 2,684,109 Youmans July 20, 1954 52,752,056 Lull June '26, 1956 2,765,996 Anderson Oct. 9, 1956 2,839,260 Jacobi June 17, 1958 2,945,242. Heiden July 19, 1960 2,989,202 De Canniere et a1 June 20, 1961 vFOREIGN PATENTS 1,032,495 Germany June 19, 1958 1,092,381

Germany Nov. 3, 1960 

1. AN INDUSTRIAL LIFT TRUCK COMPRISING A BODY HAVING WHEELS FOR ENGAGING A SURFACE ON WHICH SAID TRUCK IS TO BE OPERATED, LOAD ENGAGING MEANS, MEANS MOUNTING SAID LOAD ENGAGING MEANS ON SAID BODY FOR MOVEMENT FROM A FIRST POSITION TO A SECOND POSITION SO LATERALLY DISPLACED FROM SAID FIRST POSITION AS TO RENDER SAID TRUCK UNSTABLE WHEN HANDLING A LOAD NEAR THE CAPACITY OF THE TRUCK, AND SUCTION MEANS FOR TEMPORARILY ANCHORING SAID BODY TO SAID SURFACE DURING LOADING AND UNLOADING OPERATIONS TO PREVENT TIPPING OF SAID BODY, SAID BODY HAVING A PERIPHERY, SAID WHEELS BEING LOCATED WITHIN THE CONFINES OF SUCH PERIPHERY, SAID SUCTION MEANS EXTENDING AROUND SUCH PERIPHERY EXTERIORALLY OF SAID WHEELS. 